1. Field of the Invention
The present invention relates to a nutritious amino acid solution for intravenous feeding, particularly for those patients who have undergone a surgical operation.
2. Description of the Prior Art
From the viewpoint of nutrition and physiology, the compositions of currently used amino acid infusion solutions have need for much improvement. First of all, the compositions of commercially available solutions are based upon the knowledge of oral nutrition requirements. Thus, some typical commercial amino acid based infusion solutions have been formulated based upon the essential amino acid requirements recommended by FAO, or have been based upon a knowledge of the amino acid composition of human milk. Secondly, if an intravenous composition is not based upon oral nutrition requirements, it then is probably based upon the amino acid requirements for a healthy person, for example, the plasma free amino acid pattern of human subjects.
Generally, an amino acid infusion solution is administered intravenously to a patient who has undergone a surgical operation. Thus, the composition of the solution should be such that it is utilized most effectively when administered parenterally to patients with pathological conditions. Preferably, for such people an intravenous composition should not be used which is the same as that used for oral administration or as a composition formulated in view of the nutritional requirements of a healthy person. The reason for this is as follows. Orally administered amino acids are absorbed in the small intestine, and are then passed throughout and utilized by the body. The initial composition is modified by bacteria initiated decomposition in the small intestine followed by competitive absorption of such amino acids as valine, leucine and isoleucine in the small intestine. Thereafter, enzymatic metabolism of the amino acid occurs in the liver and so on. On the other hand, for an infusion solution which is directly supplied to the tissues of the body by injection of the infusion solution into the blood in a vein which is circulated by the blood, no change in composition of the infusion occurs upon parenteral administration. For these reasons, the optimal composition for an amino acid solution administered by infusion should be different from that administered orally.
Moreover, it is known that patients suffering from different pathological conditions show different metabolic capacities. Accordingly, the amino acid nutritional requirements for patients in different pathological states vary as disclosed by P. M. Sender et al in "Nutritional Aspects of Care in the Critically Ill", 1977, edited by J. R. Richards et al, Churchill Livingstone, page 177.
In order for an amino acid based infusion solution to be more effective from the viewpoint of nutritional physiology, the amino acid infusion solution should have a composition which meets the amino acid requirements of patients under a particular pathological state in order to keep up a normal pool of amino acids in the living body. Thus, the composition of the infusion should be selected so as to compensate for the changes which occur in amino acid metabolism in a living body under a given pathological state, and to normalize the amino acid pattern in the blood, by supplying such a solution which is truly effective from the viewpoint of nutritional physiology. It should be observed that, strictly speaking, the metabolic changes which occur for a given pathological condition and the mode of correction or normalization also vary according to the specie of animal suffering from the condition. The variations in the amino acid metabolism of man and rat are not quantitatively the same, although they show similar qualitative tendencies. Thus, it might be concluded that a composition proven to be effective for a rat or a dog might not be effective for a man. However, such compositions are far more preferred in comparison to infusion compositions which are based on oral nutrition requirements. Therefore, a need has continued to exist for infusion solutions of compositions more appropriate for patients who have undergone surgical operations and are in a given pathological state.